So I have now done an x86_64 upgrade install from FC1 followed by a
fresh install with the same partitioning on the same machine. Both times
I had issues with getting the boot loader installed. The first time it
actually crashed during install and the second time it just hung. After
the second time I went ahead and rescued it and created a grub.conf from
scratch since anaconda never made one.

With both installs Nautilus would not run so I am using KDE right now
which seems to be fine. I haven't tried xfce4 yet but I will in a few
minutes.

I've done both an update from an updated FC2T2 (just for grins) and a
clean install of FC2T3 x86_64 with no apparent issues here...nautilus
seems to run fine although I have switched from the "out in space"
mode...grub installed and works as advertised...this system is an Asus
K8V/3200.